Dear Vicki, How do I know what type of hamster I have? What are the behaviour traits of each type? There are many different breeds of hamster but the most common include Syrian, Dwarf Russian and Roborovski. Syrian hamsters are the largest breed and the most popular as pets. They must be kept alone but can become quite tame and enjoy the company of their owners. The remaining two breeds are much smaller and can be kept in same-sex small groups or pairs. They are generally more difficult to handle due to their small size and ability to move very quickly. Dear Vicki, I have a 10-year old Collie-Spaniel cross, Maya, who has always been very friendly. Recently she has started growling at my partner and at young children in the park, although she never does this with me. I’m concerned about her behaviour, could this be due to her age? In the short-term you should use a basket muzzle as a precaution when you take Maya for walks in public and never leave her unsupervised with young children. Sometimes aggression can begin later in life due to an underlying medical condition. Pain can also cause changes in behaviour. You should take her to your vet as soon as possible to check there are no health issues causing this behaviour. If Maya gets a clean bill of health, your vet can advise you on how to address her behaviour, which may involve referring you to an accredited pet behaviourist. For an introduction to behaviour problems in dogs, you can download PDSA’s free behaviour leaflet at www.pdsa.org.uk/ leaflets.